These: things are pretty hard to come by in general in the automotive aftermarket, and especially in the right length and in this quality!
Helpful: For anybody working on a D1S or D3S based headlight system and who needs a new or longer output from their ballast to the back of their bulb.
Well-made: Each connector is built to OEM standards with the proper male/female connections and rubber seals on the terminals, and the wiring is wrapped in stainless mesh to protect against abrasion and help shield any small levels of EMI that may exist.
Offered: In a couple different versions to mate with the most common OE ballast outputs, so make sure you select the style that's most appropriate for the ballast you'll be using it with! (the bulb connector is the same either way)